• Journal of Korean Elementary Science Education
• /
• v.26 no.5
• /
• pp.475-488
• /
• 2007

The purpose of this study was to investigate elementary students' difficulties when they read the illustrations on scientific textbook. 5 illustrations were selected on basis that they had some of the textual/graphical features. The data were collected from open-ended questionnaires and follow-up interviews. To investigate difficulties of reading illustrations, 100 sixth grade students participated in this study and interviews were taken to 9 volunteers among those participants. The results showed that many students had difficulties in the integration of verbal representation and realistic image representation on the illustration, therefore they often misunderstood the meaning of illustration. These results gave several recommendations when we used illustrations as educational materials. Teachers would be better to guide that students could understand illustrations with the integration of the reading of one or more representations.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.2
• /
• pp.291-295
• /
• 1998

The ovalbumins obtained from hen's and duck's egg white were irradiated with up to 100 kGy at room temperature. The purified proteins were evaluated for their in vitro digestibility by incubating successively with pepsin and pancreatin conjugate. Amino acid compositions and SDS-PAGE pattern in these proteins were also analyzed. The obtained results indicated that gamma irradiation within the tested dose range(up to 100kGy) produced no statistically significant changes in the in vitro digestibility an amino acid compositions. Analysis of gamma-irradiated ovalbumins by SDS-PAGE revealed radiolysis of ovalbumin into proteins or peptides of low molecular weights.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.178-180
• /
• 2003

This paper proposes a real-time simulator that can simulate dynamic changes of a substation for intelligent SCADA system. The simulator consists of RTDS, voltage and current amplifier, IED, and RTU. The simulator is verified by system implementation and event simulation of a substation.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.187-189
• /
• 2003

This paper presents new service restoration algorithm to deal with multiple faults such as main transformer fault, whole substation fault and simultaneous faults. The most important consideration of restoration planning for multiple outage areas is efficient use of redundant backup feeders. The proposed algorithm tries to restore all outage loads using outage area ordering method and tie switch exchange method that are newly proposed in this paper.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.2
• /
• pp.225-231
• /
• 2010

As growth of operational complexity in power systems, necessity of information integration between automation systems such as EMS, SAS, DAS and renewable energy sources has been increased. This paper proposes a new information integration architecture between power automation systems based on web service technique. Loosely coupled feature of web service system can provide more flexible and reliable way to exchange information. Communication testing on the demonstration system has been performed to establish the feasibility of the proposed architecture.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.51 no.7
• /
• pp.333-340
• /
• 2002

To secure a service continuity is one of the most important mission in the ower distribution system operation. In this paper the necessary and sufficient condition to guarantee 100% service restoration capability for any fault on the system is reported. An evaluation methodology of the restoration capability(or restorability) is developed based on the developed restoration conditions. Applications of the developed concept to the system operation in the normal and emergency states, that would enhance the supply reliability of the system are described. They include enhancement of restoration capability adapting to load change, identification of best open switch and supervised switch positions.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.53 no.5
• /
• pp.249-256
• /
• 2004

This paper suggests a novel evaluation scheme of protective effectiveness in distribution systems. The adequacy of every parameter in a protective device is evaluated for the setting or correction rules. Then, the protective effectiveness of a device, device-wise effectiveness, is obtained by the combination of the parametric evaluation results. The coordination-wise effectiveness between devices can be calculated by evaluating the parameters which contribute the performance of coordination. The protective effectiveness of the whole system can be obtained by combining the device-wise and coordination-wise effectiveness values. The rules, in this paper, are categorized into three groups; rules for single parameter, rules for coordination between parameters, and rules for coordination between protective devices to form a hierarchical calculation model. The proposed method is applied to a typical distribution network to show its effectiveness.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.52 no.2
• /
• pp.114-120
• /
• 2003

According to the use of distribution automation systems, the function to find or to search a fault phase is necessary for automatic switches in a distribution substation. In this paper, two algorithms are developed to fine the fault circuit and the fault phase for the automatic switches in substation with ungrounded power system. One is the fault circuit searching method using the zero sequence voltage at the bus and zero sequence current of circuit current and the other is to find the fault phase using the line voltage and zero sequence current. The developed algorithms are tested in the case study simulations. An ungrounded power system is modeled by EMTP as a case study system. The developed algorithms are tested in the case study simulations and each shows correct results.

• Proceedings of the KIEE Conference
• /
• 1998.07c
• /
• pp.1094-1096
• /
• 1998

An intelligent power transformer protective relaying algorithm based on fuzzy decision-making is proposed. To distinguish external faults with CT saturation, overexcitation and inrush conditions from internal faults, a newly designed fuzzy-rule base is used. The Dempster-Shafer's rule of combition is used for fuzzy inference. A series of the S/W and H/W tests show the proposed protection algorithm has practically sufficient sensitivity and selectivity.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.366-368
• /
• 2003

In this paper, a parametric evaluation method of protection ability is proposed. The adequacy of every parameter is evaluated for the setting rules. Then the results are combined to give protection level of a whole protective system. The setting rules are categorized into three groups for hierarchical calculation. The proposed scheme is applied to a location problem of a new protective device to show its effectiveness.